Crossbow dry fire arrestor and crossbow impact compensator

ABSTRACT

Disclosed in a dry fire arrestor for a crossbow having a trigger mechanism operable to fire an arrow or bolt, that includes a spring plate, trigger sear connected to the trigger mechanism, an anti-dry fire bar for engaging and disengaging the trigger sear. The dry fire arrestor utilizes tension provided by the spring plate to allows anti dry fire bar to automatically engage the trigger sear, precluding movement of the trigger when an arrow in not properly inserted in the dry fire arrestor.

PRIORITY

This application claims priority to provisional application Ser. No. 60/881,076, filed with the U.S. Patent and Trademark Office on Jan. 18, 2007, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to crossbows, and in particular to trigger mechanisms for preventing firing of a crossbow without a bolt loaded therein.

The present invention relates generally to crossbows, and in particular to a mechanism for compensating for firing error in a crossbow.

2. Description of the Related Art

Crossbows have been used since the middle ages. Crossbows have evolved to include cams and synthetic split limbs that greatly increase firing velocity. However, increased firing velocity creates a problem of damage or injury when the crossbow is inadvertently fired when unloaded, i.e. when the crossbow is discharged without a bolt (also referred to as an arrow) that is loaded, i.e. pressed against the tensioned crossbow string. Unloaded or dry firing imparts can damage the crossbow string, limbs, cams and other components. Dry firing also creates a safety concern. Further, the time required to reload a dry fired crossbow will often allow quarry to escape, which is a significant concern for crossbow hunters.

In an attempt to overcome such problems, a dry fire inhibitor has been introduced in the form of a hinge lever or finger (referred to herein as a finger) positioned along the crossbow shaft near the start of the string travel. The finger is configured to normally contact the shaft, and insertion of an arrow creates a separation between the hinge lever and the shaft. When dry fired, the string will travel a short distance and then the finger will catch the string, akin to the operation of an aircraft carrier tail hook arrestor.

Conventional dry fire inhibitors also fail to ensure proper loading of the bolt into the trigger mechanism and fail to ensure that the arrow is properly nestled against the tensioned crossbow string. Discharge when a arrow is not properly nestled against the tensioned string can result in the string becoming jammed beneath the incorrectly loaded arrow. In addition, conventional dry fire inhibitors may ride along the arrow as the arrow is discharged, reducing crossbow accuracy.

The present invention provides an arrestor that solves the problems associated with conventional crossbow dry fire inhibitors.

The present invention further provides an impact compensator that allows for one-handed dynamic adjustment for varied target range. In contrast, conventional compensators provide a one-time setting. The impact compensator is preferably provided separate from a conventional sight.

SUMMARY OF THE INVENTION

The present invention overcomes disadvantages of conventional systems by providing a self-contained dry fire arrestor that includes

The present invention provides an advantage of an automatic safety feature by immobilizing the crossbow trigger when a bolt is not properly loaded.

The present invention provides a further advantage of precluding any string travel absent proper loading of an arrow.

The present invention provides yet a further advantage of avoiding misfires and jamming.

The present invention is lightweight, reliable and can be incorporated into the trigger mechanism.

The dry fire arrestor of the present invention can, if desired, be combined with the above-described conventional dry fire inhibitors.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a cutaway view of the crossbow dry fire arrestor of the invention, in an cocked engagement state;

FIG. 2 is a dissembled view of the crossbow dry fire arrestor of FIG. 1;

FIG. 3 is a dissembled view of the crossbow dry fire arrestor of FIG. 1, also showing a trigger assembly;

FIG. 4 is a close-up view of a portion of the trigger assembly of FIG. 3;

FIG. 5 is a cutaway view of the crossbow dry fire arrestor of FIG. 1, showing a movement direction of an anti dry fire bar;

FIG. 6 is a view showing details of a slot of a trigger sear for engagement of the anti dry fire bar;

FIG. 7 is a dissembled view of the crossbow dry fire arrestor of FIG. 1, showing engagement of the trigger sear with a shoulder region of an engaging member;

FIG. 8 is a dissembled view showing both halves of the casing of the dry fire arrestor;

FIG. 9 is a top view of the jaws, showing a jaw urging member and jaw member slot;

FIG. 10 is a side view of the jaw urging member;

FIG. 11 shows compression of the jaw spring into its containment cavity;

FIG. 12 shows a partially assembled dry fire arrestor;

FIG. 13 is a perspective view through a sight mounted onto an impact compensator assembled onto the crossbow;

FIG. 14 shows the impact compensator mounted onto stock;

FIG. 15 shows the impact compensator being removed from the stock;

FIG. 16 shows manipulation of a pivoting sight of the impact compensator;

FIG. 17 shows the pivoting sight rail removed from the impact compensator;

FIG. 18 shows the pivoting sight rail assembled with the impact compensator and compensator adjusting wheel;

FIG. 19 is a perspective view of impact compensator;

FIG. 20 is a perspective view of impact compensator with the compensator wheel removed; and

FIG. 21 is a perspective view of a horizontal impact compensator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of preferred embodiments of the invention will be made in reference to the accompanying drawings. In describing the invention, explanation about related functions or constructions known in the art are omitted for the sake of clearness in understanding the concept of the invention, as such would obscure the invention with unnecessary detail.

FIG. 1 provides a cutaway view of the crossbow dry fire arrestor in an engagement, i.e. cocked, state, which is the condition of tensioning a crossbow string (not shown), which would be held between upper and lower jaws (260, 270) awaiting firing of the crossbow. Upper and lower jaws (260, 270) are shown in an open state in FIG. 12 and are shown in a closed (or cocked) state in FIGS. 1, 6 and 8.

Arrow 290 is shown being inserted between the jaws in direction “B” in FIG. 1. As shown in FIG. 9, an opening is provided at the center of each of upper and lower jaws (260, 270) through which arrow 290 is held. It is preferable to provide both upper and lower jaws (260, 270) to hold the crossbow string at a position that is not in contact with the barrel 120 of the crossbow 100, thereby reducing string wear and improving firing accuracy. In contrast, conventional crossbow string holders utilize a single action gate that presses the string against the barrel 120.

An upper curved portion of anti dry fire bar 225 is preferably provided to allow for frictional contact to hold arrow 290 in the dry fire arrestor 200.

A spring plate 210, shown dissembled from the dry fire arrestor 200 in FIGS. 1 and 2, is preferably affixed to each casing half 205 via respective affixing holes 211. The flexibility of the spring plate 210 provides upwardly biases the anti dry fire bar 225. Insertion of the arrow 290 overcomes the upward biasing force, and moves the anti dry fire bar downward (FIG. 5).

FIG. 2 shows the crossbow dry fire arrestor of FIG. 1, with a trigger sear 220 and engaging member 240 further dissembled, and with crossbow string holding jaws removed. The anti dry fire bar 225 engages and disengages with trigger sear 220, which is connected to a conventional trigger mechanism as shown in FIGS. 3 and 4. The tension provided by spring plate 210 allows anti dry fire bar 225 to automatically engage trigger sear 225, which precludes any movement of the trigger when an arrow 290 in not properly inserted in the dry fire arrestor 200. This automatic immobilizing of the trigger mechanism acts in addition to a conventional thumb safety lock. In the present invention, pressure of the crossbow string neither activates nor precludes operation of the anti dry fire mechanism.

Pulling the crossbow trigger exerts a forward motion (“A” in FIG. 1) on trigger sear 220, which abuts a shoulder region 245 of engaging member 240. As shown in FIG. 2, shoulder region 245 protrudes slightly below the otherwise flat bottom surface of jaw urging member 250.

A hole in the anti dry fire bar 225 through which trigger sear 220 passes is shown in FIGS. 2 and 6. Trigger sear 220 is provided with slot 221 that engages a lower edge of the hole when an arrow 290 is not properly inserted in the dry fire arrestor 200. Engagement of the anti dry fire bar 225 with the slot of trigger sear 220 precludes any movement of the trigger sear 220. FIG. 7 provides a dissembled view of the crossbow dry fire arrestor of FIG. 1, showing engagement of the sear 220 with a shoulder region 245 of engaging member 245, with spring 210 removed to allow the anti dry fire bar 225 to protrude below the casing 205, which will allow the jaws to remain in the cocked state.

Proper insertion of the arrow pushes the anti dry fire bar 225 downward, thereby freeing and allowing the trigger sear 220 to move forward. Forward movement of the trigger sear 220 causes the engaging member 240 to drop, thereby allowing jaw urging member 250 to move forward, resulting in upper and lower jaws (260, 270) opening via rotation about first and second jaw fulcrum (281, 282).

To provide opening/closing force for operation of the upper and lower jaws 260, 270, a jaw post 285 is provided to hold a jaw spring 287 in a compressed state within a containment cavity 288. For clarity, FIG. 8 shows jaw post 285 removed but positioned near the post groove 286 in casing 205. FIG. 9 provides a top view of the jaws, showing jaw urging member 250 and containment cavity 288. Access to the containment cavity 288 is provided via a jaw member slot 251 (FIG. 10), through which the jaw post 285 passes (see FIG. 3), and via a distal end (FIGS. 2 and 11) of jaw urging member 250. FIG. 10 provides a side view of the jaw urging member 250, showing jaw spring 287 protruding from its containment cavity via the distal end of jaw urging member 250, and FIG. 11 shows compression of the jaw spring 287 into its containment cavity for insertion of jaw spring support 288 through jaw member slot 251.

As shown in FIGS. 8-12, compression of jaw spring 287 in containment cavity 288 creates a tension force against jaw spring support 288. FIG. 12 depicts the normally open position of upper and lower jaws (260, 270), awaiting insertion of the crossbow string, which pushes forward edges of the upper and lower jaws apart, creating a rotation force about first jaw fulcrum 281 (FIGS. 1 and 7) and pushing the jaw urging member 250 in a rearward direction (arrow “C” of FIG. 1). The jaw spring 287 force opposes such rearward pushing of jaw urging member 250.

FIG. 13 provides a perspective view of the crossbow, looking through a sight 150 of impact compensator 120. As shown in FIG. 14, the impact compensator 120 is mounted onto stock 110. The sight 150 removed in FIG. 14, and FIG. 15 shows the impact compensator 120 being removed from the stock 110. FIG. 17 shows pivoting sight rail 160 removed from the impact compensator 120. When assembled, a spring force holds the pivoting sight rail 160 close to the main body 121 of the impact compensator.

As shown in FIG. 16, sight rail 160 pivots about an impact compensator pivot 135, in a rotational direction indicated by arrow “D” (FIG. 18). A compensator adjusting wheel 140 is provided to allow the user to adjust the extent of rotational movement of pivoting sight rail 160 while viewing a target through the sight 150. A retaining ring 149 (FIG. 18) is provided to rotatably hold a pin 145 of the compensator adjusting wheel 140 within a hole 146 (FIG. 20) of the impact compensator 120.

Elevational protrusions 140 a through 140 f of the compensator adjusting wheel 140 sequentially push against an elevation cam 180 affixed to the pivoting sight rail 160. The elevational protrusions 140 a through 140 f are of varying height, and a notch 181 is provided in the elevation cam 180 to retain one selected elevational protrusion 140 a through 140 f and provide the user with a click through adjustment. FIG. 20 provides a perspective view of impact compensator 120 with the compensator wheel 140 removed, showing elevational protrusions 140 a through 140 f spaced at regular interval around a circumference of the compensator wheel for contacting a shoulder region of elevation cam 180, to incrementally raise the height of the pivoting sight rail 160 as a user turns compensator wheel 140.

As shown in FIG. 18, sight 150 is attached to the impact compensator rail 160, and the pivoting movement about impact compensator pivot 125 via adjustment of compensator wheel 140 will adjust the range of the sight 150. As shown in FIG. 14, range marking are preferably provided on compensator wheel 140. It is also preferred that an outer circumference of compensator wheel 140 be abraded or knurled to enhance friction and sensitivity. 

1. A dry fire arrestor for a crossbow having a trigger mechanism operable to fire an arrow or bolt, the dry fire arrestor comprising: a spring plate; a trigger sear connected to the trigger mechanism; and an anti-dry fire bar for engaging and disengaging the trigger sear, wherein insertion of an arrow moves the anti dry fire bar, disengaging the trigger sear and allowing trigger operation.
 2. The dry fire arrestor of claim 1, wherein an arrow is inserted between upper and lower jaws.
 3. The dry fire arrestor of claim 2, an opening is provided between the upper and lower jaws through which the arrow is placed.
 4. The dry fire arrestor of claim 1, further comprising a spring plate to upwardly bias the anti dry fire bar.
 5. The dry fire arrestor of claim 1, further comprising upper and lower jaws to hold a crossbow string at a position not contacting a barrel of the crossbow.
 6. The dry fire arrestor of claim 1, wherein pressure of the crossbow string neither activates nor precludes operation of the anti dry fire mechanism.
 7. A dry fire arrestor for a crossbow having a trigger mechanism operable to fire an arrow or bolt, the dry fire arrestor comprising: a spring plate; a trigger sear connected to the trigger mechanism; an anti-dry fire bar for engaging and disengaging the trigger sear; wherein tension provided by the spring plate allows anti dry fire bar to automatically engage the trigger sear to preclude any movement of the trigger when an arrow in not properly inserted in the dry fire arrestor. 